1. Field of the Invention
This invention generally relates to a lens measuring device and method applied therein, and, more specifically, to a device for measuring lens polarity and skewness and method applied therein.
2. Description of Related Art
Optical lenses come in various types according to application scope and material composition. Optical lenses can be fabricated by many different quick mass production techniques. However, no matter what technique is adopted, accuracy is always a very important quality parameter for optical lenses.
In order to ensure accuracy of optical lenses, measuring techniques are employed, but such techniques must be able to be applied quickly in order to keep up with the mass production line and to reduce costs. Thus, the technique of measuring optical lens accuracy has become important. Therefore, after achieving the objective of efficient mass production, manufacturers and designers in the lens industry have turned their attention to how to provide a fast and easy measuring method at low testing cost for achieving the objective of ensuring optical lens accuracy.
ROC patent No. I264523 entitled “Method and Device of Interferometer for Measuring Lens Polarity and Skewness” describes a solution, involving, first, enabling the light axis of the interferometer that corresponds to a first mirror surface of the light axis of the lens to be measured to form a particular relation, and also recording a first coefficient; then, turning the lens to be measured 180 degrees, thereby enabling a second mirror surface of the light axis of the lens to be measured to form another particular relation, and also recording a second coefficient; and, last, comparing the first and the second coefficients to calculate the polarity and skewness of the first mirror surface light axis and the second mirror surface light axis.
In the abovementioned method of measuring the polarity and skewness of a lens light axis, although the polarity and skewness of the lens light axis can be obtained accurately by comparing the first and the second coefficients and calculating the correlation therebetween, the method requires two adjustments in the lens and the interferometer. Also, turning the lens to be measured 180 degrees as well as recording and analyzing two parameters are required before obtaining information on errors on the polarity and skewness of the lens to be measured.
In view of the above, although the measuring method is capable of accurately measuring lens polarity or skewness, the method involves multiple steps, thereby greatly increasing measuring time and costs.
Hence, it is a highly urgent issue in the industry to provide a technique that is capable of greatly reducing measuring time and costs, and that is also applicable to testing a plurality of lenses to be measured easily and simultaneously.